FR2728787A1 - FLEXIBLE MECHANICAL FASTENER AND DISPOSABLE PRODUCT PROVIDED WITH SUCH A FASTENER - Google Patents

Abstract

The attachment tab (10) includes a substrate (12, 14) adapted to be joined to a disposable product, such as an infant diaper, and a first mechanical attachment component (16) adapted to engage with a second mechanical fastening component, said fastening tab having a Gurley stiffness of less than 1000 mg in an area comprising said first component.

Description

The present invention relates to a mechanical fastening tab suitable for

  use on a disposable product. More specifically, the present invention relates to a mechanical fastening tab having improved flexibility. Disposable absorbent products, such as diapers for infants, incontinent adult products, and the like, are known to those of skill in the art. Likewise, the mechanical fastening means for fixing such absorbent products around the waist of a wearer are also known to those skilled in the art. Examples of known mechanical fasteners include:

  hook and loop fasteners.

  Unfortunately, mechanical fasteners, such as hook and loop fasteners, are not widely used in commercially available disposable absorbent products. One reason is that such mechanical fasteners tend to be relatively expensive and therefore difficult to use economically on a disposable product. This is especially true when mechanical fasteners are designed to have fixing properties that make them suitable for use on disposable absorbent products. Mechanical fasteners which are inexpensive enough to be used on a disposable product, on the other hand, tend to have fixing properties which are insufficient for satisfactory use on products.

disposable absorbents.

  In particular, during use, the mechanical fasteners provided on disposable absorbent products are generally subjected to both shearing and peeling forces. As used herein, the term "shear force" is intended to refer to the forces that are applied to the mechanical fasteners in a plane generally parallel to the plane of attachment between the components of the fastener. "Peeling force" means a force applied at an angle of 90 or more to separate the components of the fastener from a mechanical fastening tab in peeling mode. A mechanical fastener that does not have sufficient resistance to shearing and peeling forces would tend, when used on a disposable absorbent product, to separate, with the result that the disposable absorbent product would open and no longer be attached around the waist of the

  carrier. This is obviously undesirable.

  Consequently, there is a need for mechanical fasteners suitable for use on disposable absorbent products and which would be economical enough to allow their use on disposable products while having sufficient resistance to peeling and shearing forces for the product resulting disposable absorbent be satisfactory to

  usage. This is the goal that the invention set for itself.

  The present invention relates to a mechanical fastening tab for use on a disposable absorbent product. The attachment tab includes a substrate adapted to be joined to said disposable absorbent product. The attachment tab further includes a first mechanical attachment component joined to said substrate. The first mechanical attachment component is adapted to be releasably engaged with a second mechanical attachment component. The fastener has a Gurley stiffness value of less than about 1000 milligrams in an area of said fastener including said first mechanical fastener component. According to another of its aspects, the present invention relates to a disposable absorbent product comprising an outer envelope, possibly a lining on the body side, and an absorbent core. The disposable product further comprises a mechanical fastening tab, said mechanical fastening tab comprising a substrate joined to said disposable absorbent product and a first mechanical fastening component joined to said substrate. The first mechanical attachment component is adapted to come into releasable engagement with said outer casing. The fastener has a Gurley stiffness value of less than about 1000 milligrams in an area of said fastener including said first mechanical fastener component. In another aspect, the present invention relates to a disposable absorbent product comprising an outer shell, a body side liner and an absorbent core located between the outer shell and the body side liner. The outer shell is made of a film material to which a nonwoven material is attached to form a laminate. The laminate has a Gurley stiffness value of less than 100 milligrams. The disposable absorbent product further includes a mechanical fastening tab. The mechanical fastening tab includes a substrate joined to said disposable absorbent product and a first mechanical fastening component joined to said substrate. The first mechanical fastening component is adapted to come into releasable engagement with the laminate. The fastener has a Gurley stiffness value of less than about 1000 milligrams in an area of the fastener comprising said first mechanical fastener component. In a specific embodiment, when the first mechanical fastening component is releasably engaged with the laminate and subjected to shear forces, the laminate deforms to dissipate part of said shear forces. In another aspect, the present invention relates to a disposable product comprising an outer shell to

  which is attached a second mechanical fastening component.

  The product further includes a mechanical fastening tab.

  The mechanical fastening tab comprises a substrate joined to said disposable product and a first mechanical fastening component joined to said substrate. The first mechanical fastener component is adapted to releasably engage the second mechanical fastener component. The fastener has a Gurley stiffness value of less than about 1000 milligrams in an area of said fastener including said first mechanical fastener component. In the drawings: - Figure 1 illustrates an embodiment of a fastening tab according to the present invention; - Figure 2 is an exploded perspective view of the fastening tab illustrated in Figure 1; - Figure 3 illustrates an embodiment of a fastening tab according to the present invention; - Figure 4 is a sectional view taken along line 4-4 of Figure 3; - Figure 5 is a top plan view of an embodiment of a fastening tab according to the present invention; - Figure 6 is an exploded perspective view of the lug illustrated in Figure 5; - Figure 7 is a top plan view of an infant diaper according to the present invention; - Figure 8 is a sectional view taken along line 8-8 of Figure 7; Figure 9 is a top plan view of an embodiment of a fastening tab according to the present invention; - Figure 10 is a sectional view taken along line 10-10 of Figure 9; - Figure 11 is a top plan view of an embodiment of a fastening tab according to the present invention; - Figure 12 is a sectional view taken along line 12-12 of Figure 11; - Figure 13 is a top plan view of an embodiment of a fastening tab according to the present invention;

  - Figure 14 is a section taken along line 14-

  14 of Figure 13; - Figure 15 is a top plan view of an embodiment of a fastening tab according to the present invention; and

  - Figure 16 is a section taken along line 16-

  16 of Figure 15. The present invention relates to a mechanical fastening tab suitable for use on a disposable absorbent product. The present invention can be better understood by referring to the drawings in which the figure

  1 illustrates a fastening tab according to the present invention.

  The attachment tab 10 comprises a first substrate 12 and a second substrate 14 joined to the first substrate 12. The first substrate 12 and / or the second substrate 14 are adapted to be

  combined with a disposable absorbent product.

  A first mechanical fastening component 16 is joined to the first substrate 12. The first mechanical fastening component is adapted to come into releasable engagement with a second mechanical fastening component. The lug 10 has a Gurley stiffness value of less than about 1000 milligrams in an area of said lug

  comprising said first mechanical fastening component 16.

  The transverse end 18 of the attachment tab 10 is adapted to be assembled on a disposable absorbent product to form a "manufacturer" connection end of the attachment tab 10. By "manufacturer" connection end we refer to the portion of the fastening tab 10 which comprises a connection securing the fastening tab 10 to the disposable absorbent product, which connection is formed during the process of manufacturing the disposable absorbent product. The connection which defines the "manufacturer" connection end is generally intended to be a permanent connection so that the fastening tab can only be removed from the disposable absorbent product by destroying it. The disposable absorbent product to which the fastening tab 10 is fixed has a machine direction (SM) and a cross direction (ST). By "machine direction" we refer to the direction which corresponds to the length (as defined by the longitudinal center line) of the product. The cross direction refers to a direction generally perpendicular to the machine direction. The direction of the fastening tab 10 which is generally parallel to the machine direction of the product to which the fastening tab 10 is fixed will likewise be considered to be the machine direction of the fastening tab 10. In other words, the machine direction of the attachment tab 10 will be the direction generally parallel to the machine direction of the product to which the attachment tab 10 must be joined. In the illustrated embodiment, the direction indicated by the arrow 20 indicates the machine direction of the attachment tab 10. The direction indicated by the arrow 22 generally corresponds to the transverse direction of the attachment tab 10 in the sense that '' it is parallel to the cross direction of the disposable absorbent product to which the tab

  fastener 10 must be assembled (see Figure 1).

  FIG. 2 shows an exploded perspective view of the fastening tab 10 illustrated in FIG. 1. While the fastening tab illustrated in FIG. 1 and in FIG. 2 are shown as comprising a first and a second substrate, it should be understood that the fastening tab could comprise only a single corresponding substrate

  either to the first substrate or to the second substrate.

  As used herein, the term "first mechanical fastener component" refers to a material that is adapted to come into mechanical engagement with a second material. Any material meeting this definition is suitable for use as the first component of a mechanical fastener. In the illustrated embodiment, the first mechanical fastener component is the hook portion of a hook and loop fastener. Hook and loop fasteners are known to those skilled in the art. A hook and loop fastener generally includes a hook material and a loop material. The hook material generally includes a base sheet material from which rod-like elements project. One end of the rod is attached to the base sheet material while the other end of the rod defines a hook, or a structure similar to a

  hook such as a mushroom, which is adapted to inter-

  lock with buckle or buckle-like material. Loop or loop-like material generally includes a knitted, woven or non-woven material, defining individual loops of material which can interlock with the hook material. Loop material can be attached to a

substrate to form a laminate.

  As examples of hook materials suitable for use according to the present invention, mention may be made of the products obtained from Velcro Group Company, Manchester, New Hampshire, USA, under the designations

  CFM-22-1097; CFM-22-1121; CFM-22-1162; CFM-

-1003; CFM-29-1003.

  Suitable hook materials generally include from about 16 to about 620 hooks per cm (from about 100 to about 4000 hooks per inch2), alternatively from about 124 to about 388 hooks per cm2 (from about 800 to about 2500 hooks per inch2), and if necessary from about 155 to about 310 hooks per cm (from about 1000 to about 2000 hooks per inch2). The hooks suitably range from about 0.00254 cm (0.001 inch) to about 0.19 cm (0.075 inch), and alternatively from about 0.0381 cm (about 0.015 inch) to

  about 0.0762 cm (about 0.03 inch).

  Other hook materials suitable for use in accordance with the present invention include hook material available from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, USA, under

the designation CS 200.

  The hook material according to the present invention can be formed from a polymeric material having a flexural modulus greater than about 2.07.103 bars (30 kilolivres / inch2), suitably between about 3.45.103 bars (about 50 kilolivres / inch) and approximately, 68.103 bars (approximately 300 kilolivres / inch2), and if necessary between approximately 10.34.103 bars (approximately

At, 2

  kilo-pounds / inch), and approximately 3.45.103 bars (approximately 50 kilo-pounds / inch2). When the polymeric material from which the hook material according to the present invention is formed has a relatively high flexural modulus, this property tends to make the hook material less flexible. It follows that the fastening tab has a relatively high Gurley stiffness value. Therefore, when the polymeric material from which the hook material is formed has a relatively high flexural modulus, it is desirable to modify other aspects of the fastening tab or hook material to meet the

  Gurley stiffness target values indicated above.

  For example, the base sheet material from which the hook rods project can be made to be much thinner than that which is normally included in known hook materials. For example, the base sheet material from which the hooks project may have a thickness ranging from about 0.00254 cm to about 0.0508 cm (from about 0.001 inch to about 0.020 inch), alternatively d '' about 0.00508 cm to about 0.0381 cm (about 0.002

inch to about 0.015 inch).

  It has been found that the use of a polymeric material having a relatively high flexural modulus generally increases the peel strength of a hook material when it is engaged with a loop material. As a result, in one embodiment, a polymeric material from which the hook material is formed has a flexural modulus greater than about

6.89.103 bars.

  In an alternative embodiment, the polymeric material from which the hook material is formed is relatively flexible and has a flexural modulus less than about 3.45 × 103 bars (about 50 kilolibers / inch2). Due to the flexible nature of such polymeric materials, it is generally possible to employ a hook material having a thicker base sheet while obtaining a tether having a desired Gurley stiffness value. Other aspects of the material design to

  hooks can affect the flexibility of said material.

  For example, the orientation of the hooks, their spacing, the thickness of their support, the thickness of the hooks, and the like. Such aspects of hook design affect the flexibility of both the hook material

  in the machine direction and in the cross direction.

  It is believed that any flexible material having the physical strength desired to perform the fastening function described herein is suitable for use as the first and / or as the second substrate material (s). Examples of materials suitable for use as first and second substrates include thermoplastic or thermosetting films such as polyolefin films, polyurethane films, and the like; nonwoven materials such as polyolefins obtained by meltblowing or linked to spinning; woven materials; nonwoven composites; nonwoven composites / films; and the like. It is also possible to use stretchy elastomeric plies as the first and / or second substrate material (s). The elastomeric sheets can be made of a laminated material linked to the stretched state (in

  abbreviated SBL, according to the English nomenclature stretch-

  bonded-laminate), a laminated material bonded under necking

  (abbreviated NBL, according to the English nomenclature neck-

  bonded-laminate), an elastomeric film, an elastomeric foam material, or the like. For example, elastomeric fibrous webs obtained by meltblowing and which are suitable for use according to the invention are described in US-A-4,663,220 issued on May 5, 1987 to the names of A. Wisneski et al. Examples of composite fabrics comprising at least one layer of nonwoven textile fabric joined to a fibrous elastic layer are described in EP-A-0 110 010 published on April 8, 1987 and whose designated inventors are J. Taylor et al. Examples of NBL materials are described in US-A-5,226,992 issued July 13, 1993 to Mormon. When the substrate comprises a thermoplastic or thermosetting film, it can be formed integrally with the first mechanical fastening component. In other words, the substrate can constitute an extension of the support of the first component

mechanical attachment.

  Naturally, the physical properties of the materials forming the first and / or the second substrate (s) will affect the flexibility of the fastening tab illustrated in FIG. 1. Consequently, it is generally desirable that the materials forming the first and / or the second substrate (s) are chosen so as to be relatively flexible, to allow the fastening tab according to the present invention to have the desired Gurley stiffness value. More specifically, it is desirable that the materials forming the first and / or the second substrate (s) have a Gurley stiffness value of less than approximately 1000 mg, as a variant less than approximately 200 mg, and if necessary less than approximately 75 mg , measured at least in the machine direction. It is believed that any process capable of joining the first and second substrates to each other and / or the first mechanical attachment component to the first substrate is suitable for implementing the invention. For example, the materials can be joined using adhesives, thermal bonding (including ultrasonic bonding), puncture, a combination of these methods, and the like. In a preferred embodiment of the present invention, the first mechanical fastener component is attached to the first substrate by both adhesive and thermal bonds. Again, the method of assembling the first and / or second substrate (s) together as well as assembling the first mechanical fastening component to the first substrate can affect the flexibility (as measured by Gurley stiffness) of the attachment tab. Consequently, the assembly method must be carefully chosen to allow the lug to have the desired Gurley stiffness value. The fastening tabs according to the present invention have a Gurley stiffness value of less than approximately 1000 mg, as a variant less than approximately 500 mg, in a variant still less than approximately 200 mg, and where appropriate less than approximately 75 mg, in a area of the fastening tab comprising the first mechanical fastening component. The area of the fastening tab comprising said first mechanical fastening component and having the Gurley stiffness values described above suitably has an area of at least about 1 cm 2, and as a variant at least

about 2 cm2.

  The fastening tabs according to the present invention will be considered to have the desired Gurley stiffness values when the fastening tabs have a desired Gurley stiffness value measured either in the machine direction or in the cross direction of the fastening tabs 10. It is generally desirable that the lugs have the desired Gurley stiffness values both in the direction

machine and crosswise.

  If one refers to FIGS. 3 and 4 in which the same numerical references designate the same elements as previously, the fastening tab 10 comprises a first substrate 12 and a first mechanical fastening component 16. As can be seen in Referring to Figure 4, the first mechanical fastener component 16 includes a base sheet material 24 and hooks 26. The base sheet material is relatively thick and would tend to increase the Gurley stiffness of the tab. fastener 10 illustrated in FIGS. 3 and 4. However, the first mechanical fastening component 16 is fixed to the first substrate 12 by ultrasonic connections along connection lines 28. It has been found that the presence of connection lines 28 makes the lug 10, illustrated in Figures 3 and 4, relatively flexible in the direction

  machine 20 of the lug 10.

  The connecting lines 28 suitably have a width of between about 0.10 mm and about 0.5 mm (about 0.004 inch and about 0.02 inch), alternatively from about 0.15 mm to about 0.30 mm ( about 0.006 inch to about 0.012 inch). Likewise, the flexibility of the fastening tab 10 is affected by the frequency of the connecting lines 28. Consequently, the first mechanical fastening component 16 is suitably joined to the first substrate 12 by connecting lines 28 having a frequency from about 3 to about 12 connecting lines per 25.4 mm (per inch), and alternatively from about 5 to about 10 connecting lines per 25.4 mm (per inch) in the machine direction 20 of

the lug 10.

  The fastening tabs illustrated in FIGS. 3 and 4 will, due to the presence of the connecting lines 28, generally be more flexible in the machine direction 20 than in the cross direction 22 of the fastening tab 10. In fact, the presence of the connecting lines 28 can increase the rigidity of the lug 10 in the cross direction 22 of the lug. However, as indicated above, provided that the fastening tab 10 has a Gurley stiffness value of less than approximately 1000 mg, one obtains

  generally improved fixation.

  Figures 5 and 6 illustrate an alternative embodiment of the fastening tab according to the present invention. In the embodiment illustrated in FIGS. 5 and 6, the fastening tab 10 again comprises a first substrate 12 and a first mechanical fastening component 16. As can be seen with reference to FIG. 6, the first mechanical fastening component 16 is joined to the first substrate 12 along a transverse end 30 of the first substrate 12 so that the first substrate 12 partially doubles the first mechanical fastening component 16. In other words, the first mechanical fastening component is fixed to the first substrate 12 only on an overlapping portion 32 and is not completely doubled by the first substrate 12 in the non-overlapping portion 34. By forming the fastening tab 10 of such so that the first mechanical fastening component 16 is not fully lined by the first substrate 12, the flexibility of the mechanical fastening tab 10 can be improved in an area comprising the first mechanical fastening component. eu. When the first mechanical fastener component is not fully lined by the first substrate, it is generally desirable that about 98 to about 2%, and alternatively about 98 to%, of a flat surface of the first component home

  mechanical are not doubled by said first substrate.

  On the contrary, FIGS. 1 to 4 illustrate attachment tabs in which the first mechanical attachment component 16 is completely doubled by the first substrate 12. In other words 100% of a flat surface of the first component mechanical fastener 16 are doubled

  by a flat surface of the first substrate 12.

  Figures 7 and 8 illustrate a fastening tab according to the present invention in place on a disposable infant diaper. While the fastening tabs according to the present invention are illustrated in use on an infant diaper, it should be understood that they would be just as suitable for use on other disposable products such as incontinent adult products, and the like. . Those skilled in the art will recognize that the diaper 36 generally includes an outer shell 38, a body side lining 40 and an absorbent core 42 located between the outer shell 38 and the body side lining 40. Leg elastics 44 are located

  generally along the longitudinal edges of the diaper 36.

  The diaper further comprises a front waist elastic 46 and a rear waist elastic 48. The attachment tabs according to the present invention are generally fixed to the rear of the diaper. In the illustrated embodiment, the fastening tab has the structure shown in Figures 1 and 2. Consequently, the fastening tab is fixed by sandwiching the outer casing 38 and the body side lining 40 between the first substrate 12 and second substrate 14 in an area where the first and second substrates are not attached to each other. This

  aspect of the invention is clear from Figure 8.

  In the embodiment illustrated in FIG. 8, the diaper 36 further comprises a second mechanical attachment component 50. The second mechanical attachment component is generally located on the front of the diaper 36. In the embodiment illustrated, the first mechanical fastener component includes the hook material and the second mechanical fastener component includes a loop material. The first and second mechanical fastening components can come into mutual engagement to fix the diaper 36 around the size of a wearer. Those skilled in the art will understand that the relative positions of the hook and loop materials can be reversed on the

change 36.

  Specific examples of disposable absorbent products on which the fastening tabs according to the present invention can be used are described in the following documents: US-A-4,798,603 issued January 17, 1989 to the names of Meyer et al .; US-A-5,176,668

  issued January 5, 1993 in the name of Bernardin; USA-

  176,672 issued January 5, 1993 to the names of Bruemmer et al .; US-A-5,192,606 issued March 9, 1993 to the names of Proxmire et al .; US Patent Application 08/096,654 filed July 22, 1993 in the names of Hanson et al., and US Patent Application 08/263,281 filed June 21, 1994 in the names of Dilnik et al. An example of a loop material suitable for use as a second mechanical fastener component 50 illustrated in Figure 7 is the material obtained from Guilford Mills, Inc., Greensboro, North Carolina, USA, under

  the designations Style 19902, Style 34285 or Style 30020.

  Other materials with suitable loops are described for example in US-A-5,019,073 issued May 28, 1991 to the names of Roessler et al. Suitable loop materials can include woven, knitted or nonwoven materials. Suitable nonwoven materials are those

  formed by a spinning-topping or melting process

  blowing and which have a basis weight ranging from approximately 3.4 to 68 g / m2 (approximately 0.1 to approximately 2.0 ounces / yard2), alternatively from approximately 17 to approximately 42.5 g / m2 ( about 0.5 to about 1.25 ounce / yard2) and, if applicable, about 25.5 to 34 g / m2 (about 0.75 to about 1.0 ounce / yard2). The fibers of such nonwoven materials are suitably formed from polymeric materials such as polyolefins, polyamides, polyesters, rayon, combinations of these materials, and the like. Such nonwoven materials generally have a fiber count in the range from about 1 denier to about denier, and preferably from about 2 denier to about

5 deniers.

  The second mechanical fastener component may be a separate member located on the exterior surface of a disposable absorbent product in a manner as illustrated in Figure 7. Alternatively, the second mechanical fastener component may constitute the entire outer surface of the disposable absorbent product such that the outer shell is the second mechanical fastening component. In a specific embodiment, the outer envelope of the disposable absorbent product is a film / nonwoven laminate known as a thermally laminated material under extension (abbreviated to STL, according to the English nomenclature stretch thermal laminate) comprising a film blown polypropylene 0.015 mm (0.6 thousandths of an inch) and a material formed of

  polypropylene bonded to 23.6 g / m2 (0.7 oz / yard2) spinning.

  The spinning material is made up of fibers of about 2.0 denier. The STL material is formed by stretching the polypropylene film, in one direction, until it is 25% elongated. The polypropylene bonded to the spinning is then brought into contact relation face to face with the stretched polypropylene film. The polypropylene film and the spinning bonded material are then thermally bonded together at spaced intervals. The resulting laminate has a plurality of separate and distinct bonding sites with an overall bonding area of approximately 13% per unit area. After the film and the spinning material have been laminated on top of each other, the laminate is allowed to come to rest. The film layer shrinks by about 10%, leaving the film permanently deformed to a length which is about 15% longer than its original length. The process for forming the STL material is described in more detail in US patent application no. 07/997 800 filed December 29, 1992 in the names of McCormack et al. The inventors of the present invention have discovered that when the second mechanical fastener component is made of a nonwoven material, it is generally desirable that the hooks are relatively small, having a height which does not exceed about 0.5 mm (approximately 0.02 inch) and be present at a density of approximately 140 to approximately 280 hooks per cm2 (approximately 900 to approximately 2500 hooks per inch2). Suitable hook materials are those mentioned above under

  the references CFM-25-1003, CFM-29-1003 and CS 200.

  The inventors of the present invention have discovered that it is desirable for the second mechanical fastening component to be extremely flexible. Thus, it has been found that woven or knitted materials such as those described above are particularly suitable for use according to the present invention. For example, the loop material obtained from Guilford Mills has a Gurley stiffness value of less than about 6 mg. When the Guilford Mills loop material is adhesively attached to an STL outer shell, the loop / STL composite has a Gurley stiffness value of less than about 40 mg in both the machine and cross directions. It has been found that the STL material described above has a Gurley stiffness value of less than about 10 mg both in the machine direction and in the cross direction. The STL material is capable of fulfilling the double role of film impermeable to liquids and of the second component of mechanical fastening (loop material). Thus, the Gurley stiffness of the STL material can represent the stiffness of the second mechanical fastening component. Rather, the Guilford Mills loop material is attached to a substrate such as STL material so that the loop / STL composite can represent the stiffness of the second fastening component.

  mechanical and the material to which it is directly attached.

  The inventors of the present invention have discovered that it is desirable for the second mechanical fastener component itself (without any other attached component) to have a Gurley stiffness value of less than about 100 mg, alternatively less than about 75 mg, alternatively still less than about 50 mg and, if necessary, less than about 20 mg. It is also desirable that the second mechanical fastening component and all other components of a disposable absorbent product to which the second mechanical fastening component is directly attached has a Gurley stiffness value of less than about 1000 mg, alternatively less than about 500 mg, alternatively still less than about 200 mg, alternatively less than about 75 mg

  and, if applicable, less than about 50 mg.

  In a preferred embodiment of the present invention, the ratio between the Gurley stiffness value of the fastening tab and the Gurley stiffness value of the second mechanical fastening component is between about 1:10 and 10: 1 , and alternatively between about 1: 5 and: 1. By having the Gurley stiffness ratio of the paw

  and the second mechanical fastening component itself

  even within the ranges indicated above, an improved fixation is obtained. In another embodiment of the present invention, the ratio between the Gurley stiffness value of the fastening tab and the Gurley stiffness value of the second mechanical fastening component and of all other components of the disposable absorbent product to which the second mechanical fastening component is directly attached is between approximately 1:10 and 10: 1, and

  alternatively between about 1: 5 and 5: 1.

  In addition, when the fastening tab and the second mechanical fastening component itself are in mutual engagement relationship to form a fastening composite, it is desirable that the fastening composite has a lower Gurley stiffness value to about 1000 mg, alternatively less than about 500 mg, alternatively still less than about 200 mg and, where appropriate, less than about

75 mg.

  In one embodiment of the present invention, the second mechanical fastening component and / or a component to which it is attached is (are) able to deform during the application of shear forces when the attachment tab and the second mechanical attachment component are engaged. For example, the second mechanical fastener component may be formed from, or attached to, an elastomeric material or an extensible material having a low modulus. The ability of the second mechanical fastener component to deform when subjected to shear forces allows the shear forces applied to the second fastener component

  mechanical to be dissipated over a larger area.

  Thus the shear forces which are applied are not concentrated in the area where the fastening tab is

  in engagement with the second mechanical attachment component.

  Figures 9 to 16 illustrate specific embodiments of the fastening tabs according to the invention. Referring to Figures 9 and 10, the mechanical fastening tab 52 comprises an elastomeric material 54 which is fixed by connecting lines 56 to a lining on the body side 58. A first substrate 60 is fixed to the elastomeric material 54 in an overlap area 62. The hook material 64 is

  fixed to the first substrate 60 by adhesive layers 66.

  It has been found that positioning the hook material 64 on the first substrate 60 in an area other than the overlap area 62 increases the flexibility (reduces the

  Gurley stiffness) of the mechanical lug 52.

  Figures 11 and 12 illustrate an embodiment of the fastening tabs of the present invention similar to

  those illustrated in Figures 9 and 10.

  Consequently, the references used in Figures 11 and 12 which are identical to those used in Figures 9 and 10 denote the same elements. The attachment tabs illustrated in FIGS. 11 and 12 differ from those illustrated in FIGS. 9 and 10 in that the hook material 64 is thermally bonded to the first substrate 60 at connection points 68. It has been found that the replacement of the adhesive layer 66 illustrated in FIGS. 9 and 10 by the connection points 68 illustrated in FIGS. 11 and 12 produces a fastening tab which can be more flexible in

  reason for removing the adhesive layer 66.

  Figures 13 and 14 illustrate another embodiment of the lug 52. Again, the reference numerals used in Figures 13 and 14 which are identical to the reference numerals used in Figures 9 to 12 denote the same elements. The tab shown in Figures 13 and 14 is identical to that shown in Figures 9 and 10, except that the hook material 64 located on the end of the tab 52 opposite the fixed end to the body side lining 58 is not completely doubled by the first substrate 60. In other words, a portion 70 of the hook material 64 is not in overlapping relationship with the first substrate 60. Thus, the portion 70 of the tab 52 has increased flexibility due to the absence of an adhesive layer 66 and the absence of a first

substrate 60 in portion 70.

  Figures 15 and 16 illustrate another embodiment of the lug 52. Again the references used in Figures 15 and 16 which are identical to the references used in Figures 9 to 12 denote the same elements. The attachment tab illustrated in FIGS. 15 and 16 is similar to that illustrated in FIGS. 13 and 14 except that the first substrate 60 has been divided into two pieces, which pieces are joined to the hook material 64 to define a portion. 70 of hook material 64 which is not lined by the first substrate 60. It has been found that this also increases the flexibility of the fastening tab 52 in the sense that the

  portion 70 is not doubled by the first substrate 60.

  The clip and the hook material may have other shapes and configurations. For example, such shapes and configurations are described in the French patent application filed on the same day as the present application in the name of the same applicant and having the title "Attachment tab strongly resistant to separation

  by coat and article provided with such a fastener ".

  Gurley Rigidity Test Procedures A suitable technique for determining Gurley stiffness values is a Gurley Rigidity test, the

  description is given in TAPPI Standard Test T 543 om-94

  [paper stiffness (Gurley type stiffness tester)]. A suitable device for testing is the Gurley digital stiffness tester model 4171-D manufactured by Teledyne Gurley, 514 Fulton Street, Troy, New York 12181-0088, USA. This instrument makes it possible to test a wide variety of materials using various lengths and widths, in combination with the use of a weight of, 25, 50 or 200 grams placed in one of three positions on the index of the apparatus. In the context of the present invention, the Gurley stiffness values indicated are provided to correspond to values which

  would be generated by a "standard" size sample.

  As a result, the Gurley stiffness tester balance readings are conveniently converted to the stiffness values of a standard size sample and expressed in milligrams. A standard size sample has a width of 25.4 mm (1 inch) and a nominal length of 76.2 mm (3 inches) [actual length 88.9 mm (3.5 inches)]. The actual length of the sample is the nominal length, plus an additional length of 6.35 mm (0.25 inch) to hold the sample in the clamp and another additional length of 6.35 mm (0.25 inch) ) to cover the arm. Tables of factors for reading the scale readings generated by non-standard size samples and converting them to the stiffness reading of standard size samples are given in the instruction manual of the stiffness tester. Gurley supplied by Teledyne Gurley. Consequently, samples of other dimensions can also be conveniently used as long as the appropriate conversion factor is applied to determine the appropriate value which corresponds to the standard size sample.

EXAMPLES

EXAMPLE 1

  A fastening tab is formed using hook material available from Velcro Group Company under the trade designation CFM-22-1056 (also known as HTH-856). Hook material at a hook height (from the top surface of the base film, theoretical values) of 0.71 mm (0.028 inch) and a hook width (at the widest location, theoretical values) about 0.20 mm (about 0.008 inch). The hook material had a film

  0.23-0.30 mm thick (0.009-

  0.0012 inch), a hook density of 890 hooks per 6.45 cm2 (per inch2) and it was formed of a material

  polymer with a flexural modulus of 7.58.103 bars-

  9.65.103 bars (110-140 kilolivres / inch2).

  The hook material described above was attached to NBL material to form a fastening tab. The hook material was 44.45 mm by 12.7 mm (1.75 inch by 0.5 inch) in size. NBL material is formed as described in US-A-5,226,992 issued July 13, 1993 to Morman. The NBL material used had three layers. The two outer layers were spin-bonded polypropylene layers having a basis weight of 1.4 oz / yard2 (47.6 g / m2) and were formed from 2-3 denier fibers. The center layer was an elastomeric film having a basis weight of g / m2 and was formed from Kraton 2740X, which is a polymer resin available from Shell Chemical Company. The NBL material was 101.6 mm (4 inches) long and 69.85 mm (2.75 inches) wide. The hook material was attached to the NBL material by an ultrasonic bond (approximately 6.25% bond area) and adhesive. 34 g / m2 (1.0 oz / yard2) [25.4 mm x 19.5 mm (1.0 inch x 0.75 inch)] spunbond material was located between the hook material and the material NBL. Additional fastening tabs were formed in the same manner, except that connecting lines, such as those illustrated in Figures 3 and 4, were formed in the fastening tabs. The bond lines were about 0.5 cm wide and extended across the material in the machine direction. Three connecting lines were formed on the fastening tab. In one case, the connecting lines were distributed so that a connecting line was located approximately 0.635 cm from each end of the hook material (crosswise) and a connecting line was generally located in the center of the length of the hook material in the cross direction (coincident connecting lines). In another embodiment, three connecting lines were formed on each tether, but the connecting lines did not coincide so that the location of the connecting lines along the length, depending on the direction across, hook material varied (non-coincident connecting lines). These hook materials were then subjected to the Gurley stiffness test. The attachment tabs were then used to replace the mechanical attachment tabs supplied on commercially available HUGGIES Supreme diapers (step 4). In other words, the non-elastomeric change ears HUGGIES Supreme have been

  replaced by the attachment tabs described above.

  The changes thus formed were submitted to the appreciation of a panel of users. Mothers trained for this purpose were asked to assess a number of specific attributes during the use of the tested diapers. In this particular test, mothers were asked, among other things, to assess the degree of hook irritation and the number of untimely openings (spontaneous separation of fastening materials from hooks and loops). 60 children have

  each used the exchange model for a week.

  Thus, each child was involved in the study for a period of three weeks. Each child used the three change models (unlinked legs, with coincident connecting lines and with non-coincident connecting lines). Each of the three exchange models was used by children during each week of the study for three weeks. The results of this test are shown

in Table 1 below.

TABLE 1

  Rigidity Number Irritation Openings

Gurlw from the untimely.

  changed brackets No * lines 1818.2 1785 2.41% 1.85% linkage Link lines 98.6 1724 1.10% 3.71% coincident Link lines 438.7 1685 1.36% 2.91 % not coincident * not in accordance with the invention in mg, measured in the machine direction (average of 5 samples) As shown in Table 1, the presence of both coincident and non-coincident connecting lines results in lower irritation by the hooks. It was also noted that the number of untimely openings is increasing. This is believed to be due to the perceived increase in stiffness observed in the cross direction and which results from the presence of the connecting lines. This demonstrates the importance of flexibility in both machine and cross directions and the need to balance the flexibility properties for

achieve the desired results.

EXAMPLE 2

  The following materials were subjected to the Gurley stiffness test: 1. Hook material available from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, USA, under

the designation CS-200.

  2. An SMS material having a basis weight of 57.8 g / m2 (1.7 oz / yard2) formed of two outer layers of spin-bonded polypropylene having a basis weight of 21.25 g / m2. The intermediate layer consisted of polypropylene fibers obtained by meltblown and

  had a basis weight of 15.3 g / m2.

  3. STL material formed from a blown polypropylene film of 0.015 mm (0.6 thousandths of an inch) and a polypropylene bonded to spinning of 23.6 g / m2 (0.7 ounces / yard2). The spinning material was made up of about 2.0 denier fibers. STL material is formed as it is

described in detail above.

  4. Knitted loop material commercially available from Guilford Mills under the trade designation

Style 34285.

  5. Laminate of material 1 with material 2. The laminate is obtained by using a double-sided adhesive tape such as the tape available from Minnesota Mining and Manufacturing Company under the designation # 465. Sufficient double-sided tape is used to cover

  the facing surfaces of the two materials.

  6. Laminate corresponding to material 5 in mechanical engagement with material 3. The laminate is brought into mechanical engagement with material 3 using a standard mechanical roller of 2 kg (4.5 pounds) (available from Chemsultants International, Mentor, Ohio, USA), by rolling the roller from side to side of the materials (placed in relation to opposite) once in

each direction.

  7. Laminate of material 4 on the material 3. Laminate

  is formed as described for material 5.

  8. Material 1 in mechanical engagement with the material 3. The materials are brought in mechanical engagement as it is

described about the material 6.

  9. Laminate of material 3 on material 2, which laminate is then brought into mechanical engagement with material 1. The laminate is formed and engaged as indicated above in relation to

materials 5 and 6.

  The results of the Gurley stiffness test are shown in Table 2. The data reported in the

  Table 2 represents an average of 10 tests.

TABLE 2

  Material Sense of Rigidity Dev. standard test- Gurle2

1 SM 16.87 2.05

1 ST 16.54 1.71

2 SM 8.60 1.7

2 ST 29.69 8.51

3 SM 4.77 1.31

3 ST 6.49 5.79

4 SM 5.44 3.29

4 ST 1.39 0.47

SM 98.3 22.3

ST 185.2 24.7

6 SM 267.4 36.2

6 ST 391.9 53.9

7 SM 28.7 5.3

7 ST 37.5 6.7

8 SM 103.2 18.2

8 ST 122.5 33.5

9 SM 314.1 28.7

9 ST 335.2 52.5

  SM = machine direction; ST = cross direction 2 in mg

EXAMPLE

  The following material was subjected to a tensile test in a manner similar to that described in Test Method D-882 of the American Society of Testing and

Materials (ASTM).

  It is a laminate of a tied carded web and a film. The bonded carded web is formed from polypropylene fibers available from Hercules Inc., under the designation T-196. The tied carded tablecloth has a basis weight of 26 g / m2 (0.77 oz / yard2). The bonded carded web is laminated, using an adhesive, onto a breathable film available from The Sam Woo Corporation. The film has a basis weight of 39 g / m2. The film was formed of about 26% by weight of linear low density polyethylene, about 10% by weight of high density polyethylene, 10% by weight of ethylene vinyl acetate, about 48% by weight of calcium carbonate coated with a fatty acid, and about 6% by weight of other additives. The laminate was tested to determine its tensile strength in both the machine and cross directions. The results of this test are shown in the

Table 3.

TABLE 3

  Direction Load Deviation Deformation Maximum deviation standard maximum maximum standard

SM 759.3 45.6 269.0 138.1

ST 3704.2 295.7 39.4 3.8

  All values are expressed in grams-force.

  Maximum load and deformation values

  maximum represent the average of six trials.

  The laminate described above and a hook material available from Minnesota Mining and Manufacturing Company under the designation CS-200 was subjected to the shear test as generally described in the ASTM Method D test. -5169. The

  results of this test are shown in Table 4.

ABLEAUL4

  Direction 'Load Deviation Energy Maximum deviation 2 standard total 3 standard

SM 1377.5 695.8 0.2212 0.1343

ST 814.13 44.67 2.29 1.16

  1 direction of the shear forces applied to delaminate the material 2 in grams-force 3 tension energy absorbed at break expressed in inch-pounds per inch. This is the total area under the stress / strain curve, at the level of the maximum value, generated during the shear test. (1 inch = 25.4 mm; 1 pound = 0.4536 kg; 1 inch2 = 6.45 cm2) As can be seen from the above data, the ability of a laminate material to deform during application of shear forces greatly increases the total shear energy that can be applied to the system before the bond between the hook material

and the laminate breaks.

Claims (39)

  1 - Mechanical fastening tab (10; 52) intended to be used on a disposable absorbent product, said fastening tab (10; 52) comprising: a substrate (12, 14; 60) adapted to be joined to said absorbent product disposable; and a first mechanical fastening component (16; 64, 66) joined to said substrate (12, 14; 60), said first mechanical fastening component (16; 64, 66) being adapted to be releasably engaged with a second mechanical fastener component (50), said fastener tab (10; 52) having a Gurley stiffness value of less than about 1,000 mg in an area of said fastener tab (10; 52) comprising said first   mechanical fastening component (16; 64, 66).   2 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said first mechanical fastening component (16; 64, 66) is a material with hooks. 3 - Mechanical fastening tab (10; 52) according to claim 2, characterized in that said hook material has a Gurley stiffness value of less than approximately 1,000 mg.   4 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said fastening tab (10; 52) has a Gurley stiffness value less than about 200 mg.   - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said fastening tab (10; 52) has a Gurley stiffness value less than about 75 mg.   6 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said Gurley stiffness value is determined in the machine direction of the   mechanical fastening tab (10; 52).   7 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said substrate (12, 14; 60) covers 100% of a flat surface of said first   mechanical fastening component (16; 64, 66).   8 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said substrate (12;) covers from about 2 to about 98% of a flat surface   said first mechanical fastening component (16; 64, 66).   9 - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said first mechanical fastening component (16; 64, 66) is formed from a polymeric material having an upper flexural modulus at   approximately 45.36.103 bars (approximately 100 kilolivers / inch2).   - Mechanical fastening tab (10; 52) according to claim 1, characterized in that said first mechanical fastening component (16; 64, 66) is formed from a polymer material having a flexural modulus of between approximately 3 , 45.103 bars and approximately 20.68.103 bars (approximately 50 to about 300 kilolibers / inch2).   11 - Mechanical attachment tab (10; 52) according to claim 1, characterized in that it comprises a elastomeric material.   12 - Disposable product comprising: an outer envelope (38); and a mechanical fastening tab (10; 52) comprising: - a substrate (12, 14; 60) joined to said product disposable; and   - a first mechanical attachment component (16; 64, 66) joined to said substrate (12, 14; 60), said first mechanical attachment component (16; 64, 66) being adapted to come into releasable engagement with said envelope exterior (38), said tab (10; 52) having a Gurley stiffness value of less than about 1,000 mg in an area of said tab (10; 52) comprising said first component mechanical attachment (16; 64, 66).   13 - Disposable product according to claim 12, characterized in that said first mechanical fastening component (16; 64, 66) is a hook material. 14 - Disposable product according to claim 12, characterized in that said hook material has a value   Gurley stiffness less than about 500 mg.   - Disposable product according to claim 12, characterized in that said attachment tab (10; 52) has a   Gurley stiffness value less than about 200 mg.   16 - Disposable product according to claim 12, characterized in that said attachment tab (10; 52) has a   Gurley stiffness value less than about 75 mg.   17 - Disposable product according to claim 12, characterized in that said first mechanical fastening component (16; 64, 66) comes into releasable engagement with said outer casing (38) and in that it is subjected to forces of shear, said outer shell (38) deforming to dissipate part of said shear forces 18 Disposable product according to claim 12, characterized in that it further comprises a body side lining (40; 58) and an absorbent core (42 ) located between said outer casing (38) and said side lining body (40; 58).   19 - Disposable product according to claim 12, characterized in that said substrate (12, 14; 60) doubles 100% of a flat surface of said first attachment component mechanical (16; 64, 66).   - Disposable product according to claim 12, characterized in that said substrate (12; 60) doubles from about 2 to about 98% of a flat surface of said first   mechanical fastening component (16; 64, 66).   21 - Disposable product according to claim 12, characterized in that said outer envelope (38)   has a nonwoven outer surface.   22 - Disposable product according to claim 21, characterized in that said outer envelope (38)   includes film / non-woven laminate.   23 - Disposable product according to claim 21, characterized in that said outer envelope (38) has a   Gurley stiffness value less than about 100 mg.   24 - Disposable product according to claim 21, characterized in that said outer envelope (38) has a   Gurley stiffness value less than about 75 mg.   - Disposable product according to claim 21, characterized in that said outer envelope (38) has a   Gurley stiffness value less than about 50 mg.   26 - Disposable product according to claim 12, characterized in that said fastening tab (10; 52) and said outer envelope (38) are engaged to form a fastening composite, which has a Gurley stiffness value less than 1,000 mg.   27- Disposable product according to claim 12, characterized in that said fastening tab (10; 52) and said outer envelope (38) are engaged to form a fastening composite, which has a Gurley stiffness value less than 500 mg.   28 - Disposable product according to claim 12, characterized in that said attachment tab (10; 52) and said outer envelope (38) are engaged to form an attachment composite, which has a Gurley stiffness value less than 200 mg.   29 - Disposable product according to claim 12, characterized in that said fastening tab (10; 52) and said outer envelope (38) are engaged to form a fastening composite, which has a Gurley stiffness value less than 75 mg.   - Disposable product according to claim 12, characterized in that said outer envelope (38) further comprises a second mechanical fastening component (50). 31 - Disposable product according to claim 30, characterized in that said second attachment component   mechanical (50) includes a loop material.   32 - Disposable product according to claim 31, characterized in that said loop material is chosen from the group consisting of woven materials, materials   nonwovens and knitted materials.   33 - Disposable product according to claim 12, characterized in that said attachment tab (10; 52) includes an elastomeric material.   34 - Disposable absorbent product comprising: an outer cover (38) comprising a film material to which a nonwoven material is attached to form a laminate, said laminate having a Gurley stiffness value of less than 100 mg; a body side lining (40; 58); an absorbent core (42) located between said outer shell (38) and said body side lining (40; 58); and a mechanical fastening tab (10; 52) comprising: - a substrate (12, 14; 60) joined to said product disposable; and   - a first mechanical fastening component (16; 64, 66) joined to said substrate (12, 14; 60), said first mechanical fastening component (16; 64, 66) being adapted to come into releasable engagement with said laminate , said fastening tab (10; 52) having a Gurley stiffness value of less than about 1,000 mg in an area of said fastening tab (10; 52) comprising said first mechanical fastening component (16; 64, 66).   - Disposable absorbent product according to claim 34, characterized in that said first mechanical fastening component (16; 64, 66) is a material with hooks. 36 - Disposable absorbent product according to claim 34, characterized in that said hook material has a   Gurley stiffness value less than about 500 mg.   37 - Disposable absorbent product according to claim 34, characterized in that said attachment tab (10; 52) has   a Gurley stiffness value of less than about 200 mg.   38 - Disposable absorbent product according to claim 34, characterized in that said attachment tab (10; 52) has   a Gurley stiffness value of less than about 75 mg.   39 - Disposable absorbent product according to claim 34, characterized in that said laminate has a value of   Gurley stiffness less than 75 mg.   - Disposable absorbent product according to claim 34, characterized in that said laminate has a value of   Gurley stiffness less than 50 mg.   41 - Disposable absorbent product according to claim 34, characterized in that, when said fastening tab (10; 52) and said laminate are engaged to form a fastening composite, the fastening composite has a value of   Gurley stiffness less than 1,000 mg.   42 - Disposable absorbent product according to claim 34, characterized in that, when said fastening tab (10; 52) and said laminate are engaged to form a fastening composite, the fastening composite has a value of   Gurley stiffness less than 500 mg.   43 - Disposable absorbent product according to claim 34, characterized in that, when said fastening tab (10; 52) and said laminate are engaged to form a fastening composite, the fastening composite has a value of   Gurley stiffness less than 200 mg.   44 - Disposable absorbent product according to claim 34, characterized in that, when said fastening tab (10; 52) and said laminate are engaged to form a fastening composite, the fastening composite has a value of   Gurley stiffness less than 75 mg.   - Disposable absorbent product comprising: an outer envelope (38) comprising a film material to which a nonwoven material is attached to form a laminate, the nonwoven material forming the outer surface of said laminate, said laminate having a Gurley stiffness value less than 100 mg; a body side lining (40; 58); an absorbent core (42) located between said outer shell (38) and said body side lining (40; 58); one (10; 52) comprising: - a substrate (12, 14; 60) joined to said disposable absorbent product; and - a first mechanical fastening component (16; 64, 66) joined to said substrate (12, 14; 60), said first mechanical fastening component (16; 64, 66) being adapted to come into releasable engagement with said nonwoven material of said laminate, said tab (10; 52) having a Gurley stiffness value of less than about 1,000 mg in a region of said tab (10; 52) which comprises said first component mechanical fastener (16; 64, 66), whereby when said first mechanical fastener component (16; 64, 66) is releasably engaged with said nonwoven material of said laminate and is subjected to forces of shear, said laminate deforms to   dissipating a portion of said shear forces.   46 - Disposable absorbent product according to claim, characterized in that said first attachment component   mechanical (16; 64, 66) is a hook material.   47 - Disposable absorbent product according to claim 45, characterized in that said hook material has a   Gurley stiffness value less than about 500 mg.   48 - Disposable absorbent product according to claim, characterized in that said attachment tab (10; 52) has   a Gurley stiffness value of less than about 200 mg.   49 - Disposable absorbent product according to claim, characterized in that said attachment tab (10; 52) has   a Gurley stiffness value of less than about 75 mg.   - Disposable absorbent product according to claim, characterized in that said laminate has a value of   Gurley stiffness less than 75 mg.   51 - Disposable absorbent product according to claim, characterized in that said laminate has a value of   Gurley stiffness less than 50 mg.   52 - Disposable absorbent product according to claim 45, characterized in that said outer envelope (38)   is a thermally laminated material under extension.   53 - Disposable absorbent product according to claim 46, characterized in that said outer envelope (38) is an elastomeric material.   54 - Disposable product comprising: an outer envelope (38); a second mechanical fastener component (50) attached to said outer casing (38); and a mechanical fastening tab (10; 52) comprising: - a substrate (12, 14; 60) joined to said product disposable; and   - a first mechanical attachment component (16; 64, 66) joined to said substrate (12, 14; 60), said first mechanical attachment component (16; 64, 66) being adapted to come into releasable engagement with said second fastening component, said   mechanical fastener (10; 52) having a Gurley stiffness value of less than about 1,000 mg in a region of said fastener (10; 52) comprising said first mechanical fastener component (16; 64, 66) .